Blackboard eraser cleaner



Oct. 10, 1944. E. K. RITTER BLACKBOARD ERASER CLEANER Fiiea Aug. 21, 1943 Patented Oct. 10, 1944 UNITED STATES PATENT OFFICE BLACKBOARD ERASER CLEANER Elizabeth K. Ritter, Simi, Calif.

Application August 21, 1943, Serial No. 499,534

Claims.

The. invention has for an object to provide a compact and inexpensive device well adapted for installation in school rooms, for the cleaning of chalk and the like from the erasers customarily used for wiping black-boards to erase characters and drawings therefrom. It is an important aim of the invention to present a construction which is of such simple character that it may be readily operated by school children, and which will be rugged in character, so that it will be liable in a minimum degree to damage or excessive wear incident to such use as may be expected thereof in school-rooms.

It is also an aim of the invention to present a device of this character which will collect the dust from such erasers, so that cleanliness in the school-rooms will be enhanced, as well as the health of pupils safe-guarded from the effects of dust which now customarily is quite noticeable at times in school-rooms.

A further important aim of the invention is to present a construction of device adapted to take conventional erasers as now constructed and standardized for school use.

A still further important aim of the invention is to present a novel construction of brush and feeder device combined, which will effect the loosening of chalk in such erasers as Well as the brushing thereof in an effective manner.

Additional objects, advantages and features of invention reside in the construction, arrangement and combination of parts involved in the embodiment of the invention, as will be understood more clearly from the following description and accompanying drawing, wherein Figure 1 is a vertical sectional view of my invention, with part of the rotor shown in elevation.

Figure 2 is a sectional view on the line 22 of Figure 1.

Figure 3 is a similar view on smaller scale, showing the device at a different position in its operation.

Referring to the drawing, there is illustrated a cleaner device, comprising a casing Id of suitable form, having base flanges ll adapted to be secured to Wainscot trim I2, or other support suitable for the purpose. Arranged transversely in this casing I0, and carried in suitable bearings l3, on respective end walls I4 and I5, there is a revoluble shaft l6, upon which a bevelled gear I! is fixed in any usual way, next to the wall l5 of the case. The shaft is tenioned to extend through the bearing l3 upon the wall I5,

and at its outer end is provided with a handcrank 19 by which the device is operated.

Immediately inward of the bevelled gear I! a cam 20 is fixed upon the shaft, and a similarly shaped cam alined with the first is secured upon the opposite end of the shaft next to the wall 14 of the case, as indicated at 2|. A rotor 22 is mounted upon the shaft between the two cams, this rotor comprising substantially rectangular end plates 23 alined with each other and connected at their ends at each side of the shaft by respective grids 24 of suitable construction for the purposes described hereinafter.

Each of the cams is formed with two lobes 25, with continuous eccentric outer surfaces extending from a low point 26 to a high point 21, at which there is a drop portion 28 extending to the low point of the next lobe. Pivoted at each side of the casing in alinement with the respective cams, there are pendant agitator arms 29 and 36, one being mounted upon the end wall l5, and the other upon the end wall 14 near the base of the casing and at the upper part, as illustrated in Figures 1 and 2. It will be noted that the casing is extended more from the shaft l6 toward the base of the casing than toward the outer part, so that room is afforded for oscillation of the arms 29 and 30 upon their pivots between the cams and the supporting surface l2 upon which the device is mounted. Each end wall of the case is provided with an opening as at 3|. Each end wall of the case is provided with an opening as at 3|, in Figure 2, of a size sufficient to permit the insertion of an eraser longitudinally therethrough, and the arms are shaped so as to clear the opening at times sufficiently to permit the insertion of erasers, as will be understood. Connected between the two arms, there is an eraser holder consisting of a channel piece 32 of a width and depth sufficient to receive the head block 35 of a conventional chalk eraser, positioned so that the eraser may be slidingly inserted longitudinally therein, with the felt portion 34 extended inwardly toward the aids of the rotor parallel therewith. Each of the arms 29 and 30 is formed with an inward extension 36, which projects a distance inwardly beyond the normal inner face of an eraser engaged in the device, this projecting part constituting a wiper, which rests upon the respective cam for operation of the arms in unison, for the purpose of agitating and beating erasers mounted in the device.

In order to press the eraser and the said arms inwardly for proper operation, a transverse bar 31 is mounted between the walls l4 and I5, extending entirely across the case horizontally at its base, and between this bar and the brush holder, a protractile, helical spring 38 is confined. Upon one of the arms of the eraser holder devices, in this instance the arm 39, at the left-hand side of the device, a manual operating pin or arm 39 is fixed, extending outwardly through a curved slot 40 in the wall of the casing, so that the brush-holding device may be manually retracted to its outer position with respect to the rotor, so as to receive a brush therein, or permit the removal of one already cleaned, through the openings 3|.

Mounted between the end plates 23 of the rotor, there are baille or beater plates 4|,in the present instance being planiform plates parallel to the shaft and at right angles to the major dimensional line of the plates 23. These plates 4! have rectangular edges parallel to the shaft 15, one edge of each plate being positioned so as to move in the same are with the adjacent side bar of the grid 24 in operation of the rotor, while the other edge is projected outwardly much further, so as to move in an arc of greater radius. Between these two plates at opposite sides of the rotor, respective brushes 42 are mounted, being carried upon sheet metal supports 43, each having a central planiform portion parallel to the shaft i5, and having inturned end portions 44 parallel to each other, and secured to the end plates 23 of the rotor, as may readily be seen in Figure 2. The body portions of each of these plates, while parallel to the shaft H5, yet are inclined with respect to the plates 23, so that one edge moves in an arc of greater radius than the other. Upon these plates respective brush heads 45 are fixed, the outer portions of which are curved so as to present a cam-like face eccentric to the shaft l6 but parallel thereto, and in this curved face of the head, the bristles of the brush are set, as at 45. The bristles 46 all being of the same length as set in the brush, it will be apparent that their outer ends in efiect, have a cam arrangement with respect to the path of movement of the brush, which corresponds to the outer face of the head 45, as may be readily seen in Figure 2.

It will be noted thatthe drop portions 28 of the cams are located in a plane closely adjacent the medial longitudinal plane of the plates 23, mid-- way between the brushes, and at right angles to the plates 4|.

At the lower side of the casing, a well extension 48 is formed, its axis being radial with respect to the shaft l6, and being open at its outer part, terminating in a cap fitting 49, of oircularform, having a peripheral flange 50 in which pressed threads are formed to receive corresponding threads of a small glass jar or the like, in which 'water may be placed; an annular body of felt 52 being also introduced into the jar, and in the water, extending to the top of the cap 49 above the level of water in the jar. The cap 49 is provided with lateral dust-vent openings as at 53; at suitable intervals. A U- shaped bracket 54 is mounted upon the wall |5 radially in the wall portion 48, a revoluable shaft 55 being mounted in the arms of this bracket coaxially with the wall and the jar 5|. Upon the inner end of this shaft, a small bevelled gear 56 is fixed, meshed with the large gear I'Lbefore described, and between the adjacent arm of the bracket 54 and the small gear a protractile helical spring 51 is confined, so as to hold the small gear in mesh with the larger gear. Upon the opposite end of the shaft 55, an air impeller 58 is fixed, adapted to propel air from the direction of the casing l0 through the well and to the felt 52 for outward movement through the vent 53. V

The slot 4|] will afford sufiicient ingress of air for the purposes of the invention, but if desired, additional inlet openings may be formed in the casing H3 wherever required.

It should be observed that at the position shown in Figure 2, the low parts of the cams will be adjacent the -wiper portions 36 of the erasercarrier, so that the latter is at its inner limit of movement toward the shaft l5, stopped by the eraser resting on the grid 24. At the same time that the bristles of the brush 42 pass against the eraser, the high portion of the cams will engage the wipers of the eraser carrier, the high portions of the cams will support the eraser holder so that the advancing edge of the plate 4| will not engage against the eraser, nor will the advancing edge of the grid 24. However, as the grid reaches a position nearly or quite parallel to the opposed face of the eraser, the wipers 36 of the arms 29 and 36 of the eraser-carrier will drop from the high point of the lobes 25 of the cams so that the spring 38 is permitted to thrust the eraser inwardly abruptly, so that it strikes flatly against the grid work 24. Particles of chalk and dust are thereby jarred from the eraser and caused to pass inwardly through the grid toward the adjacent plate 4| which thus serves as a baflle, preventing the particles from being projected into the brushes. All dust and particles dislodged either by the brushes or by the heating effect of the grids and plates 4| will be drawn off by the current of air induced by the impeller 58, and collected in the felt 52 below the well 48 at the bottom of the casing. Removal of the eraser is efiected by again operating the bar 39, and then pushing a finger through one opening 3|, when the eraser is ejected through the opposite opening 3|.

In the operation of this device, it will be understood that the operator will stand facing the support l2 upon which the casing is mounted, in convenient position for the operation of the crank I9 by the right hand. Operation of the crank will move the gear I! and rotor in a clockwise direction, as contemplated. The operator first presses the bar 39 rearwardly, and then inserts an eraser through one side of the casing, into the channel member 32, as indicated in'Figure 2, and when the eraser is positioned so that its ends will clear the walls I4 and I5 of the casing, the bar 39 is released, permitting the spring 38 to press the eraser holder toward the rotor, where it will be stopped by engagement with either the grid 24, the edges of the plate 4|, or one of the brushes 42. The crank I9 is then operated briskly, and in this operation, from the position shown in Figure 2, the adjacent low edge of the plate 4| and the parallel edge of the adjacent grid will first wipe across the face of the felt material 35 of the eraser, working the fiber so as to loosen up impacted cloth, and this will be followed quickly bythe lower bristles 46 of the brush 42 following. The brush will press with gradually increasing force against the eraser, due to the trailing part being higher than its advancing edge, and a thorough brushing of the felt will thus occur. Engagement of the brush with the felt will be followed by agitation of the eraser felt and slapping thereof by the grid, and efiect a further loosening of the chalk packed in the body of the felt.

While I have described my invention with great particularity, in its best construction as thus far developed, it will, nevertheless, be understood that this is purely exemplary, and that various modifications in the construction, arrangement and combination of parts, substitution of materials, substitution of mechanical equivalents, improvements in designs and selection of materials may be made without departing from the spirit of the invention, except as may be more specifically indicated in the appended claims.

It should be noted that the slope of the lobes of the cams is such that the radius of the cam surface increases while passing the wiper in a degree greater than the increase in radius of the brush following, considered from the advanced edge of the brush to its trailing edge. The result is that the high part of the cam is of such maximum height that the brush is supported at least in part by the cam at the final stage of movement of the brush past the eraser, while in the earlier part of the movement the brush alone sustains the pressure of the eraser entirely. This reduces the destructive effect on the bristles at the trailing edge of the brush which would be manifest as they pass from the eraser, otherwise,

as the entire pressure of the eraser would be effective on the last row of bristles, whereas in the earlier part of movement of the brush against the eraser, several of the longitudinal rows ,of bristles are effective in sustaining that pressure.

The cams do not lift the eraser from the brush or lessen the pressure of the eraser on the brush in the earlier stageof movement of the brush against the eraser, as will be evident.

I claim:

1. An eraser cleaner of the character described, comprising a case body adapted to be mounted upon a support, a rotor revoluble in the case, means exteriorly of the case for operating the rotor, said case having openings therein to receive an eraser by longitudinal insertion on an axis parallel to that of the rotor, means within the case to receive an inserted eraser and hold the same yieldingly pressed toward the rotor, alternated beater and brush devices carried by said rotor in engaging relation to an inserted eraser, said rotor including a cam device having lobes with high portions and drop portions, said means for holding the erasers including wiper elements engaged with said cam for agitation of carried erasers, said drop portions being out of line with said brush element of the rotor, said rotor including a grid means to contact and check inward movement of an eraser short of engagement of said wipers with the low parts of said cams.

2. An eraser cleaner of the character described, comprising a case body adapted to be mounted upon a support, a rotor revoluble in the case, means exteriorly of the case for operating the rotor, said case having openings therein to receive an eraser by longitudinal insertion on an axis parallel to that of the rotor, means within the case to receive an inserted eraser and hold the same yieldingly pressed toward the rotor, alternated beater and brush devices carried by said rotor in engaging relation to an inserted eraser, said rotor comprising a brush and a grid device,

said grid in one of its positions being substantially in a plane to lie parallel to an engaged eraser, said rotor including a cam device having a lobe with a high portion terminating in a drop part adjacent said grid, the means for holding the eraser comprising a carrier having a wiper positioned to engage the cam, and arranged to clear said drop portion when said grid is alined with the eraser,

3. An eraser cleaner of the character described, comprising a case body adapted to be mounted upon a support, a rotor revoluble in the case, means exteriorly of the case for operating the rotor, said case having openings therein to receive an eraser by longitudinal insertion on an axis parallel to that of the rotor, means within the case to receive an inserted eraser and hold the same yieldingly pressed toward the rotor, alternated beater and brush devices carried by said rotor in engaging relation to an inserted eraser, a well extension being formed on the casing, a bevel gear fixed with relation to the rotor, a radial counter shaft in the well having a small bevel gear meshed with the first named gear and having an air impeller connected therewith in said well extension, said well extension including dust collecting and air venting means.

4. An eraser cleaner of the character described, comprising a case body adapted to be mounted upon a support, a rotor revoluble in the case, means exteriorly of the case for operating the rotor, said case having openings therein to re ceive an eraser by longitudinal insertion on an axis parallel to that of the rotor, means within the case to receive an inserted eraser and hold the same yieldingly pressed toward the rotor, alternated heater and brush devices carried by said rotor in engaging relation to an inserted eraser, said rotor including a cam having a lobe with a drop part operative beyond the trailing edge of the brush devices, the cam face being of gradually increased radius from a low part to a high part adjacent the trailing edge of the brush devices, and wiper means on the eraser carrier engaging the same, arranged so as to support the eraser pressure at least in part.

5. An eraser cleaner of the character described, comprising a case body adapted to be mounted upon a support, a rotor revoluble in the case, means exteriorly of the case for operating the rotor, said case having openings therein to receive an eraser by longitudinal insertion on an axis parallel to that of the rotor, means within the case to receive an inserted eraser and hold the same yieldingly pressed toward the rotor, alternated beater and brush devices carried by said rotor in engaging relation to an inserted eraser, said brush devices being eccentric to the axis of the rotor with a low advanced edge and curved brush face of gradually increased height, said rotor including a cam having a lobe beside the brush devices with a drop part operative beyond the trailing edge of the brush devices, the cam face being of gradually increased radius from a low part adjacent said advanced edge of the brush devices to a high part adjacent the trailing edge of the brush devices, its radius increasing within the arc of the brush devices more than the radius of the brush devices increases from advanced to trailing edge, and wiper means on the eraser carrier engaged with the cam.

ELIZABETH K. BITTER. 

